Many situations arise that require the transfer of fluids from one point to another. This can be quickly and easily accomplished using motorized pumps to generate the transferring force. However, there are many instances where electric pumps are not available or are not adapted to be used in the particular environment. In these particular situations, siphons are commonly used to accomplish the transfer of fluid.
Siphons generally include a tube that is used to transfer fluid to a lower level along a path including an intervening portion of relatively higher elevation. Once the fluid in the tube reaches the peak of the elevation, its weight (associated with the force of gravity) generally provides the impetus to create a continuous flow due to the elevational difference between the fluid source and receiver. The main difficulty is to get the fluid from the source through the portion of the tube that climbs the elevation. The common use of siphons often involves the user sucking on the outlet end of the tube to draw the liquid to the point in the tube where the force of gravity takes over. This procedure is not only time-consuming and tiresome but can also be hazardous when the transferred fluid is a dangerous substance such as gasoline or the like which is not to be ingested.
Improvements to siphon assemblies have included the provision of a valve device on the source end of the siphon tube. One such device is disclosed in U.S. Pat. No. 4,414,997 to Jacobson et al. The valve assembly includes a valve body with inlet and outlet ports connected by a flow cavity. A cup-shaped valve member is receivable within a valve seat formed in the inlet end of the body. The valve member oscillates within the flow cavity between its seated position and an unseated position when the siphon assembly is shaken up and down. When the valve element is in the seated position, fluid is prevented from flowing around it and through the valve body out of the siphon tube. Alternatively, when the valve element is in the unseated position, fluid is allowed to flow around it and through the valve body into the siphon tube. Once a sufficient amount of fluid has entered the tube, gravity generates continuous siphon flow.
The Jacobson valve assembly allows the user to generate siphon flow without the user having to suck on the outlet end of the siphon tube. More particularly, the valve assembly is shaken in an up and down manner to gradually force the fluid into the siphon tube and up the elevation to the critical point where gravity takes over. As the valve assembly is moved in the downward direction during priming, fluid forces the valve member to an unseated position and fluid is allowed to flow around the member into the siphon tube. When the assembly is moved in the upward direction, the valve member is urged into the seated position, preventing the fluid already in the siphon tube from escaping. Continuous up and down movement forces the fluid higher and higher in the siphon tube until it reaches the critical point where the force of gravity creates continuous siphon flow.
While this valve assembly has proven effective in many applications, it is not without its drawbacks. When in the unseated position, the valve member occupies a substantial amount of the volume within the flow cavity. In addition, the available flow area leading to the siphon tube as the valve member sits against the upper inner flange of the valve body next to the flared portion of the flow cavity is limited. Both of these design aspects tend to partially restrict the fluid flow and under certain conditions create problems relating to turbulence at various points within the flow cavity, resulting in irregular and slower flow. Further, if the valve assembly comes to rest upright on the bottom surface of the fluid source, the inlet port is completedly blocked, substantially halting the fluid flow that has been created.
A need is therefore fully identified for an improved siphon assembly and more particularly an improved priming valve that not only functions to efficiently generate continuous siphon flow but also allows smooth and rapid flow around the valve element and through the valve body. Such a siphon assembly would allow the user to create continuous siphon flow without having to suck on the outlet end of the siphon tube and prevent the need to constantly monitor the siphon operation.